I am able to successfully import gpx data to Google My Maps. Most of the gpx files I have imported are in English and I am able to move them into same layer. However, some gpx files are in another language and they can't be placed on the same layer as the English ones. Are there some tricks or tools to convert the gpx file to same format as the others?
One of the things that you might be able to do is download google earth pro and load the files there, organize them all under one folder and then right-click the root folder > "save place as" > save as a KML file